[15.01] Measuring the Velocities of Young Stars in Ophiuchus

Young stars are born in giant molecular clouds (GMCs) which
have turbulent line widths of roughly 1-2 km/s. This study,
in collaboration with the COMPLETE (Co-ordinated and
Molecular Probe Line and Thermal Emission) Study of
Star-forming regions, aims to measure whether the stars born
within these clouds share the same velocity distribution.

If young stars have a substantially higher velocity
dispersion than their gas, then studies of star formation
which look only directly at GMCs will miss all the quick
young stars which have left the area, impacting, among other
things, estimates of star formation efficiency.

Some young stars are kicked out of their birthplace with
high velocities due to supernovae or dynamical ejection.
These runaways are worth study on their own merits, since it
has recently been discovered that one such object (PV Ceph)
is moving at 22 km/s with respect to the gas it is imbedded
in, and yet appears to have an accretion disc which would
probably be stripped off by any ejection mechanism.

Through a combination of many all-sky surveys, this project
attempts to measure both the general velocity dispersion of
young stars and identify possible runaway young stars in the
Ophiuchus molecular complex. COMPLETE observations of this
region provide the necessary reference frame (the location
and velocity distribution of the star-forming gas) for this
study.

If you would like more information about this abstract, please
follow the link to jfoster@cfa.harvard.edu.
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